Effect of a 0.05% Nickel Addition to Zinc Melt on the Mutual Diffusion Coefficient of Iron and Zinc in the Formation of a Zinc Coating

• Published in: Surface investigation, x-ray, synchrotron and neutron techniques x-ray, synchrotron and neutron techniques, 2023-12, Vol.17 (6), p.1282-1286
• Main Authors: Bondareva, O. S., Rosenstein, E. O., Dobychina, O. S.
• Format: Article
• Language: English
• Subjects: Additives; Alloying additive; Chemistry and Materials Science; Diffusion barriers; Diffusion coefficient; Diffusion layers; Galvanizing; Grain boundaries; Iron; Materials Science; Nickel; Surfaces and Interfaces; Thickness; Thin Films; Zinc coatings
• ISSN: 1027-4510; 1819-7094
• DOI: 10.1134/S102745102306006X

We study the structural formation of a zinc coating obtained by immersion in a pure zinc melt with the addition of 0.05% nickel at a temperature of 450°C. The growth of the zinc coating is determined by the ζ phase and is described by a parabolic law. The degree of the equation of the approximating parabolic function is 1/5 due to the strong effect of diffusion along the grain boundaries on the bulk diffusion process. The coefficient of the mutual diffusion of iron and zinc in the ζ phase is calculated in two ways: by the thickness of the diffusion layer and using a probability diagram. The results obtained are in good agreement with each other. In a pure zinc melt, the diffusion coefficient in the ζ phase reaches the maximum value upon galvanizing for 1 min. As the exposure time increases, the diffusion coefficient decreases and remains practically unchanged at a galvanization time of 3–5 min. Galvanization in a melt with 0.05% nickel shows a significant difference in the diffusion coefficient only after 1-min exposure time, which is 2.5 times lower than in a pure melt. This means that nickel acts as a diffusion barrier and has an inhibitory effect on the process of the mutual diffusion of iron and zinc. The found regularities of the diffusion processes make it possible to control effectively the structural formation of the coating and significantly increase the efficiency of the search for new alloying additives for zinc melt.